Heavy metals availability in lake sediments using chemical extraction and X-ray fluorescence techniques

Aiming to evaluate contamination degree by heavy metals in bottom sediments at the lakes at the Santa Gertrudes region, Sao Paulo State, Brazil, where ceramic industries of enameled pavement are installed, bottom sediment samples were collected in two lakes, in different seasons (rainy season and dry season). To determine biological availability metal concentrations (no-residual fraction), and the residual fraction (geological matrix), acid extraction procedure were implemented. To enhance analytical sensibility, the obtained extracts were preconcentrated by complexation with ammonium pyrrolidine dithiocarbamate. To determine the complexed metals concentration, were used the analytical technique energy dispersive X-ray fluorescence analysis (EDXRF). To produces characteristic X-rays it was used an X-ray tube, and to detect the characteristic X-rays, a Si(Li) detector. The X-ray net intensities were obtained using the AXIL software. In the analyzed samples were possible to determine the elements V, Cr, Mn, Fe, Co, Ni, Cu, Zn and Pb. (author)